Table of Contents. Work Plan, LFG System Expansion. Former Fort Ord, California

Transcription

1 Landfill Gas Design Basis Memorandum

2 Table of Contents List of Attachments...ii List of Acronyms and Abbreviations...iii 1.0 Introduction Site Description Objectives Scope of Work GCCS Design Approach Engineering Scope of Work Design Basis Site Conditions Surrounding Site Conditions Geologic Structure Hydrogeologic Conditions ARARs Federal (RCRA Subtitle D) Monterey Bay Unified Air Pollution Control District (MBUAPCD) Solid Waste Characterization Data LFG Generation Prediction Design Criteria LFG Thermal Treatment Capacities LFG Design Methane / LFG Flow Data VOC Treatment Basis Thermal Treatment System Selection Updated Cost Analysis Enclosed Flare Selection Criteria Blower Criteria LFG Equipment Controls Equipment Construction Facility Access and Appearance Equipment Location Equipment Foundation Requirements LFG Collection System LFG Wells LFG Collection System Piping Condensate Collection Field Condensate Drainage Condensate Conveyance and Processing LFG Condensate Generation Estimates Revision 0 i

3 List of Attachments Attachment 1 Attachment 2 Attachment 3 Attachment 4 Attachment 5 Attachment 6 LFG Generation Model Results Condensate Generation Estimates Pipe Size Calculations Construction Cost Estimates Life Cycle Cost Analysis Blower/Flare Foundation Calculation Revision 0 ii

4 List of Acronyms and Abbreviations Army U.S. Department of the Army ARAR Applicable or Relevant and Appropriate Requirements DBM Design Basis Memorandum EPA U.S. Environmental Protection Agency GAC/KMnO 4 Granular activated carbon and potassium permanganate GCCS LFG Collection and Control System gpd gallons per day HDPE High Density Polyethylene LEL lower explosive limit LF landfill LFG landfill gas MBUAPCD Monterey Bay Unified Air Pollution Control District m 3 /Mg cubic meter/milligrams MMBtu/hr British Thermal Unit/hour MSL mean sea level OU2 Operable Unit 2 scfm standard cubic feet per minute SVE Soil Vapor Extraction VOC Volatile Organic Compound w.c. water column Revision 0 iii

5 1.0 Introduction This Design Basis Memorandum (DBM) summarizes the design basis to be incorporated into the construction plans and specifications for a landfill gas (LFG) treatment and control system for the Fort Ord Operable Unit 2 Landfill Areas. The design basis includes background information, project objectives and scope clarifications, site constraints, and initial values for the proposed engineering parameters. The primary objective of the DBM is to summarize the engineer's preliminary project approach for initial review, comment, and ultimate concurrence by the client's representatives. This DBM provides a tool to assure that the design approach is consistent with the client's objectives prior to expending substantial design efforts. This DBM was prepared for the U.S. Department of the Army (Army) by Shaw Environmental, Inc. (formerly IT Corporation) under the Total Environmental Restoration Contract II No. DACW05-96-D Site Description Fort Ord is a former U.S. Army installation that comprises approximately 46 square miles in northwestern Monterey County, California. In 1990, Fort Ord was placed on the U.S. Environmental Protection Agency (EPA) National Priority List, primarily due to volatile organic compounds (VOCs) found in groundwater beneath the Fort Ord Operable Unit 2 (OU2) Landfills. OU2 is a closed waste disposal facility, operated between 1960 and 1987 by the Army. OU2 was originally located north and south of Imjin Road in the Main Garrison Area. The facility consisted of six distinct landfill areas (Areas A through F). Area A, covering approximately 33 acres, was the only landfill north of Imjin Road and has been removed (clean closed). Areas B through F (south of Imjin Road) encompass approximately 120 acres. Landfill Areas B through F are unlined landfills that have been closed with composite geomembrane and soil covers. Twenty-one passive LFG vents were installed through the final covers in the 5 landfill areas. Area F has an active LFG migration control system consisting of 11 perimeter vapor extraction wells extracting LFG from the sandy soils immediately east of the Area F waste limit. Eighteen additional perimeter wells have been proposed for installation, to completely encircle Area F. Granular activated carbon and potassium permanganate (GAC/KMnO 4 ) adsorption units are used to treat the LFG by removing the regulatory constituents of concern (primarily VOCs). 1.2 Objectives The overall objective of the project is to design a cost-effective LFG collection and control system (GCCS) that is able to remove and treat a substantial portion of the VOCs being Revision 0 1-1

6 generated in OU2. Based on current adsorbent replacement rates, the existing GAC/KMnO 4 combination may not be sufficiently cost-effective to provide a large scale, long-term control solution for LFG control from OU2. Thus, developing the required design parameters for thermal treatment alternatives will be given primary consideration in this DBM. The Army has retained Shaw to design, permit, and prepare construction documents for an active GCCS. The primary objectives of the full-scale active GCCS are: To maximize LFG and VOC extraction from around landfill Area F. To reduce sub-surface transport of LFG and VOCs off-site and to groundwater. To comply with the applicable and/or relevant and appropriate requirements (ARARs) of local, state, and federal regulatory agencies. To treat and discharge the collected LFG and LFG condensate to minimize impacts on the public, the surrounding land uses, and the environment, in general. Revision 0 1-2

7 2.0 Scope of Work 2.1 GCCS Design Approach The GCCS project area has been defined as Landfill Areas E and F, for this phase of work. Areas E and F are the largest and youngest waste areas, and would be expected to be generating the bulk of the LFG produced by OU2. The preliminary GCCS design approach is assumed to be as follows: 1. LFG will be extracted from approximately 29 vertical LFG extraction wells installed for lateral migration control around the entire perimeter of Area F. These extraction wells will be operational before finalizing the GCCS design, in an interim effort to reduce ongoing VOC transport from Area F to groundwater. Based on recent monitoring data, the gas flows from the existing 11 well system have insufficient methane concentration to auto-combust in a thermal treatment system. 2. Potential sources of primary burner fuel under consideration for a thermal treatment system are: an existing 600-foot long sub-cover gas collection trench installed in Area E new interior LFG extraction wells in Area F a propane storage tank with routine propane deliveries 3. The productivity of using LFG extracted from the interior of the landfill areas cannot be accurately estimated in theory, as the quantity, composition, and age of the disposed materials is very poorly documented. LFG productivity and costeffectiveness of using the collection trench installed in Area E has been evaluated via a LFG field pumping test to determine the methane generation potential. 4. Cost analysis indicates that fueling with propane may be slightly more cost effective in the short-term (8 to 10 years) as compared to constructing additional LFG extraction wells in the interior of Area F. In the long-term (10 to 20 years), the cost of constructing interior wells could potentially pay back, in terms of reduced supplemental fuel and total removal of compounds of concern. An assumed requirement of five interior LFG wells was made for the preliminary cost evaluation. 5. In the thermal treatment unit, the extracted perimeter soil vapor will be discharged into the combustion zone of the main burners, such that the VOCs will be heated and destroyed to the required standards, before the exhaust gases released to the atmosphere. 6. Interim storage tanks will be provided at low points in the GCCS to collect condensate generated during the conveyance of the LFG. The condensate will be periodically pumped from the tanks into a water trailer and discharged to the headworks of the existing OU2 groundwater treatment system. Revision 0 2-1

8 7. The GCCS design and installation will conform to the ARARs and current best site practices. 2.2 Engineering Scope of Work The engineering scope of work includes: 1. Assisting site crew with field engineering of Area F perimeter system and Area E collector trench vent extensions (in progress) 2. Estimating theoretical methane generation potential from Area E and Area F 3. Initial sizing and selection specification for a cost-effective thermal treatment unit for treating gas from the Area F perimeter system 4. Preparing preliminary layout of a permanent thermal treatment facility 5. Preparing preliminary design layout of an (optional) interior LFG well system for Area F, to fuel a thermal treatment unit, assuming Area E collection trench has insufficient methane. 6. Preparing preliminary construction budget estimates for the thermal treatment facility and LFG well layouts. 7. Preparing final layout, connection details, technical specifications, and construction estimate for the thermal treatment facility, LFG wells and piping, and condensate system. Revision 0 2-2

9 3.0 Design Basis 3.1 Site Conditions Landfill (LF) site location: LF type, classification: LF site property area: LF refuse area: LF operation status: LF cover LF bottom liner Fort Ord, Fort Ord, California trench and fill, primarily MSW with some potential for other military waste approximately 120 acres Area F ~35 acres, Area E ~20 acres Closed 24 of foundation soil, linear-lowdensity polyethylene geomembrane, and 24 of vegetative soil layer No base liner First year of fill Approximately 1960 (Area A) 1970 for Area E 1977 for Area F Last year of fill: Method of fill: Approximately 1987 for Area F Approximately 1977 for Area E Trench and fills (parallel trenches approximately 30 feet wide, 10 to 15 feet apart, and 10 to 30 feet deep) Waste in place: Total OU2 approximately 1,000,000 tons; Area F approximately 466,000 tons; Area E approximately 265,000 tons Waste density: 1,000 lbs/cy Elevation range of closure Approximately 190 to 208 landfill surface: feet mean sea level (MSL) (Area F) Elevation range of LF bottom: Total waste depth range: Approximately 180 to 203 feet MSL (Area F) 10 to 30 feet Revision 0 3-1

10 Landfill side slope: Passive LFG vents: 3.2 Surrounding Site Conditions Nearest Residences Structures on site: Electrical power 3.3 Geologic Structure Principal geologic unit Common rock types 3.4 Hydrogeologic Conditions Groundwater elevation Groundwater flow Leachate in Landfill Varies, 33 percent maximum, 2.8 percent minimum 21 vents along top deck ridge lines of Areas B through F north, west, east of Area A perimeter; approximately 320 feet to the southeast limit of Area F (approximately 2,250 feet from the LFG treatment facility location). None on Areas B through F 100A, 480V, 3-phase electrical service is available at the existing LFG treatment facility. Sand dune, minimal fines No bedrock at relevant depths First encountered ~70 feet below ground surface. West to east Saturated waste zones are unlikely, due to transmissivity of surrounding sand. 3.5 ARARs Federal (RCRA Subtitle D) CH 4 concentration standards At property boundary: In onsite facility structures: Condensate: Less than 100 percent of the lower explosive limit (LEL)(5.0 percent by volume) Less than 25 percent of the LEL (1.25 percent by volume) Not permitted to be returned to landfills without a composite liner Revision 0 3-2

11 3.5.2 Monterey Bay Unified Air Pollution Control District (MBUAPCD) The site capacity is less than 3.27 million cubic yards, and stopped receiving waste before 1987, therefore MBUAPCD Regulation IV, Rule 437 and Federal Landfill New Source Performance Standards (NSPS) do not apply. MBUAPCD Regulation II (New Sources) and Regulation X (Toxic Air Contaminants) Rule 207 and Rule 1000: Limit emissions of total and individual organic compounds (VOCs) such as: benzene, vinyl chloride, tetrachloroethene, trichloroethene, and methylene chloride. Most individual OCs: Vinyl chloride: Less than 25 pound per day (lbs/day) Less than 5.48 lbs/day Emission limits are expressed in terms of allowable increased risks of no more than 1 in 100,000 (health-based). Compliance with the requirements of the MBUAPCD will be required prior to operating the treatment system. 3.6 Solid Waste Characterization Data Site specific data No site-specific records Waste inflow rates (tons/year) Waste composition, moisture No available data No available data content, percent Waste in place (1987): Approximately 466,000 tons in Area F, 265,000 tons in Area E 3.7 LFG Generation Prediction Since landfill operating records do not exist, the potential LFG quantities requiring control will be estimated using a combination of methods: 1. Methane generation rates based on EPA LandGEM theoretical modeling (Attachment 1), using typical municipal solid waste assumptions: Waste-in-place mass: As assumed in Section 3.1 Generation kinematics: Recovery efficiency: k = 0.03/yr (semi-arid area), L o = 100 cubic meter/milligrams (m 3 /Mg) 85 percent Revision 0 3-3

12 2. Extrapolation of soil vapor extraction rates based on the system flow for the eastern Area F perimeter system. These assumptions are: Maximum LFG flow available: Methane content: Radius of influence: 140 standard cubic feet per minute (scfm)/50 hrs/week (spring, 2003) 6.8 percent 150 feet+ 3. Data obtained from the Area E vent trench extraction flow testing (June 2003). These assumptions are: Equilibrium LFG flow available: 11 scfm, continuous Methane content: 28 percent Revision 0 3-4

13 4.0 Design Criteria 4.1 LFG Thermal Treatment Capacities Based on the ongoing site operations and the LFG generation modeling, thermal treatment equipment capacities may be required to cover a wide range of flow conditions, depending on the cost/benefit of extending the GCCS coverage. The resultant projections of LFG generation modeling are provided in Attachment 1 and summarized in Section LFG Design Methane / LFG Flow Data Year Table 1a Theoretical LFG Flow Generation Estimates EPA LandGEM Model Area F Estimated Generation Rate (scfm) Area E Estimated Generation Rate (scfm) Total Area E & F Estimated Generation Rate (scfm) Total Area E & F Estimated Recovery (scfm) Current LFG Generation Note: Estimated generation rates assume 50 percent methane concentration, k = 0.03 yr -1, L 0 = 100m 3 /Mg Year Table 1b Theoretical Methane Flow Generation Estimates EPA LandGEM Model Area F Estimated Generation Rate (scfm) Area E Estimated Generation Rate (scfm) Total Area E & F Estimated Generation Rate (scfm) Total Area E & F Estimated Recovery (scfm) Current Methane Generation Note: Estimated generation rates assume 50 percent methane concentration, k = 0.03 yr -1, L 0 = 100m 3 /Mg Revision 0 4-1

14 The current estimated LFG extraction flows from existing facilities are summarized in Table 2 below. Table 2 Current Landfill Gas Extraction Field Flows Year Area F (East) Estimated Extraction Rate (scfm) Area F (Perimeter) Projected Extraction Rate (scfm) Area E Vent Trench Estimated Extraction Rate (scfm) Current (2003) Soil Vapor Extraction (SVE) Current Methane Note: Current Area F (East) extraction rate assumes 140 scfm over 198 hours operating per month at 6.8 percent methane concentration (average flow conditions, April through July, 2003). Area F (Perimeter) projected extraction rate assumes extrapolation of Area F (East) rate to 24/7 operation. Area E Vent extraction rate assumes equilibrium flow conditions attained during July 2003 field test. The estimated required LFG treatment capacities, extrapolated from current estimated LFG extraction flows from existing facilities, are summarized in Table 3 below. Year Table 3 Treatment System Capacity Extrapolations Area F (Perimeter) Estimated Extraction CH4 (scfm) Area E Vent Trenches Estimated Extraction 28% CH4 (scfm) Area F Interior Wells Estimated Extraction 50% CH4 (scfm) Total Scenario Estimated Extraction Rate (scfm) Resultant % Methane Scenario 1, LFG Flows NA Scenario 1, Methane NA 12.3 Flows Scenario 2, LFG Flows Scenario 2, Methane Flows Scenario 3, LFG Flows Scenario 3, Methane Flows Scenario 4, LFG Flows 52 NA 47 (@ 25% CH4) Scenario 4, Methane Flows 4.3 NA Scenario 1: Area F perimeter SVE wells + Area E vent trenches. Scenario 2: Area F perimeter SVE wells + Area E vent trenches + Area F interior wells Scenario 3: Area F perimeter SVE 50% reduced extraction rate+ Area E vent trenches + Area F interior wells Scenario 4: Area F perimeter SVE 50% reduced extraction rate + Area F interior wells, 2013 projection Area F Interior Wells extraction rate estimate assumes 75% recovery efficiency of residual of LandGEM estimate, after perimeter system capture. Revision 0 4-2

15 4.1.2 VOC Treatment Basis The current estimated VOC mass throughputs for existing facilities are summarized in Table 4a below. Year Table 4a Current Area F Extraction Flow VOC Estimates Area F (East) Estimated Concentration (μg/m 3 ) Area F (East) Estimated Concentration (ppmv as hexane) Area F (East) Estimated Extraction Rate (lbs/day) Area F (Perimeter) Estimated 24/7 Extraction Rate (lbs/day) 2001 TO-14 15, VOCS 2001 vinyl 1, chloride Total NMOC TO-14 VOCs) 46, The estimated VOC treatment throughput, extrapolated from current estimated LFG extraction flows from existing facilities, are summarized in Table 4b below. Table 4b Treatment System VOC Capacity Extrapolations Year Area F (East) Estimated Extraction Rate (27% on-line) (lbs/day) Area F (Perimeter) Estimated Extraction Rate (100% on line) (lbs/day) Area F (Perimeter+Interior) + Area E trenches Estimated Extraction Rate (100% on line) (lbs/day) 2003 methane 2.5 scfm 9.3 scfm 40.3 scfm 2001 TO VOCS 2001 vinyl chloride Total NMOC TO-14 VOCs) VOC mass flows are assumed to be proportional to extracted volume of methane, based on 2001 VOC concentrations and 2003 LFG extraction flows from 11 eastern test wells in Area F. 4.2 Thermal Treatment System Selection Two types of thermal systems are in widespread use for treatment of LFG and soil vapor VOCs, the enclosed ground flare and the recuperative thermal oxidizer. The enclosed ground flares are generally of larger capacity, and are typically used where sufficient methane is available in the waste gas to auto-combust and destroy all the associated VOCs. The recuperative thermal Revision 0 4-3

16 oxidizer is generally used for smaller, more dilute hydrocarbon waste gas streams, which typically require supplemental fueling to maintain the temperature conditions for VOC destruction. The proposed enclosed ground flare is designated Best Available Control Technology for municipal landfill emissions, by the EPA. The proposed flare design has a capacity for 100 scfm LFG as primary burner fuel, plus 150 scfm of dilute soil vapor as combustion air. These quantities are near the low end of the capacity range for enclosed flares. Many thermal oxidizer manufacturers target treatment of dilute VOC streams in the size range under consideration. Typically, supplementary fuel (propane or natural gas) is required, to maintain stable combustion conditions. The proposed thermal oxidizer design has a capacity of 200 scfm of dilute soil vapor. With a soil vapor methane concentration of approximately 2 percent by volume, the manufacturer estimates that additional fuel equivalent to approximately 20 gallons per day of propane will be required to maintain proper combustion temperature. Environmental thermal oxidizers are typically fabricated of lighter weight materials than enclosed flares, are slightly more complex, and thus tend to have shorter operating lives. The permanent LFG treatment facility for OU2, Area F has been designed around an enclosed LFG flare, assuming that sufficient LFG methane is available from the proposed Area F interior wells. A supplementary propane supply will also be included in the facility design. If sufficient methane becomes unavailable, supplementary propane can be added to richen the fuel mixture or a recuperative thermal oxidizer may be readily substituted for the enclosed flare equipment package Updated Cost Analysis The cost analysis for the two thermal treatment alternatives has been updated, based on current conditions, equipment manufacturer quotes, and actual unit costs for LFG system construction. LFG system construction estimates have been prepared for three alternative installation elements and are included in Attachment 4: Installation of an enclosed LFG ground flare (assuming sufficient LFG methane is available for fueling the primary burners) Installation of a recuperative thermal oxidizer with supplemental propane fueling (assuming sufficient LFG methane is not available.) LFG collection system expansion with 5 extraction wells in the western interior of Area F Revision 0 4-4

17 The construction cost estimates were combined with realistic operating costs to provide total lifecycle costs for the most probable LFG system operating scenarios for OU2 (Attachment 5). The results of these analysis are summarized in Table 5. Table 5 - LFG Treatment Cost Update Summary Treatment Construction / Operations Scenario Project Size (scfm) Initial Capital Cost ($) 10-Year Total Costs ($) 20-Year Total Costs ($) 20-Year I = 3% ($) Thermal Oxidizer w/ propane supply SVE: , ,000 1,500,000 1,106,000 Enclosed Flare w/ Area F interior LFG wells SVE: 150 LFG: , ,000 1,383,000 1,061,000 NPV = net present value of 20 year series of annual costs, assuming the discount rate for deferred funding at 3% per annum. Based on this life-cycle cost analysis, the most cost-effective treatment option is contingent on sufficient LFG methane production being available from the proposed interior wells in Area F. If sufficient LFG methane is not available from Area F to sustain auto-combustion in an enclosed flare, the thermal oxidizer would likely be more cost effective, due to more efficient auxiliary fuel usage. The thermal oxidizer is also more cost effective over shorter life cycles, due to potentially high initial cost of installing LFG wells in a military landfill. The thermal oxidizer, operating primarily on supplemental propane, may also entail less potential downside risk, due to the undefinable quantity and quality of LFG in Area F, both currently and in the future. 4.3 Enclosed Flare Selection Criteria If a conventional LFG flare is specified as the thermal treatment unit, the following selection requirements are applicable: Enclosed flare (no exposed flame) required Flare emission performance and monitoring features should comply with applicable federal, state, and local regulatory requirements Cylindrical or conical welded shell, for even heat distribution Large self-cleaning burner orifices, to minimize cleaning requirements Minimum primary fuel concentration of 25 percent methane-equivalent is required to guarantee 98 percent VOC destruction efficiency in an enclosed flare Select thermal oxidizer unit to handle current flow rates from Table 3, Scenario 1 (minimum expansion): Revision 0 4-5

18 Current flow: approximately 148 scfm at 8.3 percent methane in 2003 [0.75 British Thermal Unit/hour (MMBtu/hr)] Select enclosed flare to handle current maximum flow rates from Table 3, Scenario 2: Maximum flow: approximately 205 scfm at 20 percent methane in 2003 (2.5 MMBtu/hr) Select enclosed flare to handle minimum flow rates from Table 3, Scenario 4: Minimum flow: approximately 99 scfm at 16 percent methane in 2018 (0.8 MMBtu/hr) Overall turndown range required (in heat capacity), 2.5 to 1.0 MMBtu/hr = 2.5: Blower Criteria For conveying the soil vapor from the proposed 29 perimeter wells around landfill F: Selection requirements: Flow rate, maximum: Flow rate, minimum: Discharge pressure required at maximum flow rate: Discharge pressure required at minimum flow rate: Vacuum required at maximum flow rate: Vacuum required at minimum flow rate: 1 existing centrifugal blower with the following design flow rate and pressure specifications. 150 scfm 90 scfm +10 inch water column (w.c.) +4 inch w.c. -70 inch w.c. -40 inch w.c. Blower construction must be spark-proof and rated for combustible gas Blower motor to be totally enclosed, fan cooled A second smaller blower will be required to convey the primary fuel LFG from the landfill interior, separately from SVE, to maintain required primary combustion zone conditions. Revision 0 4-6

19 4.3.2 LFG Equipment Controls The thermal equipment controls are to be based on use of programmable logic controller, to reduce manual operations labor. Auto start/stop on timer Auto start/stop after power failure Flame safeguard control Auto opening of LFG and SVE inlet valves by compressed air Auto closure of LFG and SVE inlet valves by compressed spring Auto shutdown and alarm indication/transmission on main flame failure, high temperature, blower surge, and power failure Alarm indicator/transmission on, propane low pressure, low temperature Auto alarm with remote notification to client designated personnel Continuous LFG flow metering and recording Continuous stack temperature monitoring and recording Equipment Construction LFG blower(s), condensate knockout pot, thermal combustion device, all associated piping, valves and fittings, and electrical control panel to be mounted on a heavy-duty structural steel skid. Single-phase and 3-phase electrical service are available onsite Facility Access and Appearance Chain link fence with wind screen on three sides, to enclose the treatment facility Gravel all-weather driveway to be provided from access road to treatment equipment location Equipment Location Thermal equipment location to be finalized based on analysis of site conditions, including: Power service availability Accessibility for vehicles and operators Low public visibility Locate central to LFG main headers from Areas E and F Revision 0 4-7

20 Maintain minimum 50-foot clearance from overhead construction (power poles, cables, trees, etc.) Prevailing wind and potential exhaust plume dispersion Equipment Foundation Requirements Provide cast-in-place concrete slab on grade for anchoring of blower/flare skid Slab design calculations required (Attachment 6), based on equipment dead and live loads, and site soil conditions Preliminary soil bearing capacity review is required, based on site soils 4.4 LFG Collection System LFG Wells The perimeter LFG wells for Area F have been previously designed by others. Interior LFG wells will be positioned in the likely locations of soil berms between fill trenches (high ground on past aerial photographs). Other design criteria for the interior LFG wells are as follows: General location: Maximum LFG well spacing: Setback from edge of refuse: LFG well boring diameter: LFG well boring depth, maximum: LFG well boring depth, range: LFG well perforated casing length: LFG well casings: Top deck crown of Area F Approximately 300 to 400 feet, on center Approximately 200 feet minimum inches 70 feet b.g.s. or minimum 20 feet above groundwater table 50 to 70 feet Well depth minus 20 feet - Size, perf. (bottom) section: 4-inch - Size, top section: 4-inch - Materials, bottom: High Density Polyethylene (HDPE), SDR-17 - Materials, top: HDPE, SDR-17 Monitoring: Access to casing interior; sample port at wellhead. Wellhead to include provisions for flow and vacuum control, gas constituent monitoring and temperature monitoring Revision 0 4-8

21 LFG well boring backfill: - Bottom to 1-foot above perf. casing: 1 3 inch washed rounded stone - Over washed rock: 2-foot thick bentonite seal - Over bentonite seal: Fine-grained on-site soil - Over fined grained soil: Second 2-foot thick bentonite seal, integrated with final cover membrane LFG Collection System Piping Material Size: Construction: Routing: Pipe: HDPE SDR-17 Fittings: HDPE SDR-11 4-inch to 6-inch (to minimize friction losses between wells and treatment facility per calculations in Attachment 3) Shallow trench with 6-18 inches of compacted native soil cover Perimeter piping to be on native soil (outside limit of waste) except at select locations. Route piping to facilitate drainage of condensate to minimum number of low point collection sumps and to keep wells and lateral pipes free draining. Pipe slopes: Inside limits of waste: Outside limit of waste: Valves: 4 percent minimum 0.5 percent minimum Wafer-type PVC butterfly valves on main piping, enclosed in valve box. Viton seat and seals, stainless steal shafts No automated valve actuation for header switching. Pressure and flow monitoring ports to be installed in hand holes every 250 to 350 feet along header, to enable pressure profile measurements and to help locate GCCS air leaks. Revision 0 4-9

22 Vaults Vault lids Lightweight, reinforced concrete or thermoplastic composites, to match existing facilities. Lightweight, salt-air-corrosion resistant, locking lids 4.5 Condensate Collection Field Condensate Drainage GCCS lateral piping on the waste surface shall be aligned to take advantage of the top deck grades to provide gravity drainage of condensate from interior wells to the main LFG header. Condensate flow through control valves shall be concurrent with LFG flow where possible. GCCS header piping shall be aligned to minimize the number of low spots for condensate accumulation. Header drain points shall be down-facing tees, minimum 4-inch diameter Condensate Conveyance and Processing Condensate collection system will consist of a small sub-grade sump, located at every low spot in the LFG header. Sump/tank will be cross-linked polyethylene, capacity to allow 14-day storage of maximum anticipated condensate production, for tributary wells. Provide sump/tank with (air sealed) connections for condensate inlet pipe, pump hose quick-connectors, venting, and 8-inch flange stub for future pump installation. Sump/tank will be installed in outer dual-containment, consisting of concrete pipe section with cast-in-place concrete floor. Condensate will be manually pumped from the collection sump and trucked to existing OU2 groundwater treatment facility for treatment. Provide gravel driveway access to each sump location. Sump/tanks inlet shall be designed to allow future retrofit with dedicated condensate pumping system. 4.6 LFG Condensate Generation Estimates Condensate generation estimates are based on LFG generation estimates in Section 3.7 and calculation of liquid formation, assuming the LFG is saturated at the well head. The calculations of total condensate are provided in Attachment 2 and the results are summarized in Table 6 below. Specific capacity requirements for each condensate sump location will be estimated by proportioning the estimated total condensate generation rate over the number of tributary wells. Revision

23 Table 6 LFG Condensate Generation Estimates Based on EPA LandGEM Model Year 2003 (current) Area F EPA with AP-42 LFG Extraction (scfm) Area E EPA with AP-42 LFG Extraction (scfm) Area F Max. Condensate Generation (gpd) Area E Max. Condensate Generation (gpd) Total Max. Condensate Generation (gpd) Actual Condensate Generation (gpd) 94 NA 43 NA (leg 96 hrs/week) NA NA NA Revision

24 Attachment 1 LFG Generation Model Results

25 Attachment 1 List 4 Fort LF Operating Procedures 1 Page 1 of 1 Attachment 1

26 4 Fort LF Model Results Methane Emission Rate Methane LFG Year Refuse In Place (Mg) (Mg/yr) (Cubic m/yr) (scfm) (scfm) E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E Attachment 1 Page 1 of 1 4 Fort LF

27 Operating Procedures Model Parameters Lo : m^3 / Mg ***** Use r Mode Selecti * k : /yr ***** User Mod e Selection ***** NMOC : ppmv ***** User Mode Selection ***** Methane : % volume Carbon Dio xide : % vol ume Landfill Parameters Landfill type No Co-Disposal Year Opene d : 1969 Current Year : 1978 C Year: 1979 Capacity : Mg Average Acceptance Rate Req from Current Year to Closure Year : 3005 /year Model Results Year Refuse In Place Methane Emission Rate Methane LFG (Mg) (Mg/yr) (Cubic m/yr) (scfm) (scfm) E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E Attachment 1 Page 1 of 2 Operating Procedures

28 Operating Procedures Model Results Year Refuse In Place Methane Emission Rate Methane LFG (Mg) (Mg/yr) (Cubic m/yr) (scfm) (scfm) E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E Attachment 1 Page 2 of 2 Operating Procedures

29 Attachment 2 Condensate Generation Estimates

30 Attachment 2 List LFG Condensate Estimates 60 scfm LFG Condensate Estimates 70 scfm LFG Condensate Estimates 80 scfm LFG Condensate Estimates 94 scfm California Temperature Normals 1 Page 1 of 1 Attachment 2

31 Project Name: FORT ORD LANDFILL - OU2 AREA F Date: 2/10/2003 Project No.: By: SN LFG CONDENSATE ESTIMATE LFG CONTROL SYSTEM DAILY GENERATION - SUMMARY TABLE PERIOD: WINTER SPRING SUMMER FALL TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) FLO (gp AVG. HIGH AVG. LOW DAILY TOTAL PERIOD: 3 DAY WORST CASE 3 DAY BEST CASE LFG FLOW DATA TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) AVG. HIGH MAX. SYSTEM VACUUM -70 in. w AVG. LOW MAX. SYSTEM PRESSUR 15 in. w DAILY TOTAL AVG. LFG WELL TEMP. 95 F MAX. LFG FLOW 60 scfm Attachment 2 Page 1 of 1 LFG Condensate Estimate 60 scfm Attachment F

32 Project Name: FORT ORD LANDFILL - OU2 AREA F Date: 2/10/2003 Project No.: By: SN LFG CONDENSATE ESTIMATE LFG CONTROL SYSTEM DAILY GENERATION - SUMMARY TABLE PERIOD: WINTER SPRING SUMMER FALL TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) AVG. HIGH AVG. LOW DAILY TOTAL PERIOD: 3 DAY WORST CASE 3 DAY BEST CASE LFG FLOW DATA TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) AVG. HIGH MAX. SYSTEM VACUUM -70 in. w.c. AVG. LOW MAX. SYSTEM PRESSURE 15 in. w.c. DAILY TOTAL AVG. LFG WELL TEMP. 95 F MAX. LFG FLOW 70 scfm Note: denotes user input value FLOW (gpd) Attachment 2 Page 1 of 1 LFG Condensate Estimate 70 scfm Attachment F

33 Project Name: FORT ORD LANDFILL - OU2 AREA F Date: 2/10/2003 Project No.: By: SN LFG CONDENSATE ESTIMATE LFG CONTROL SYSTEM DAILY GENERATION - SUMMARY TABLE PERIOD: WINTER SPRING SUMMER FALL TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) AVG. HIGH AVG. LOW DAILY TOTAL PERIOD: 3 DAY WORST CASE 3 DAY BEST CASE LFG FLOW DATA TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) AVG. HIGH MAX. SYSTEM VACUUM -70 in. w.c. AVG. LOW MAX. SYSTEM PRESSURE 15 in. w.c. DAILY TOTAL AVG. LFG WELL TEMP. 95 F MAX. LFG FLOW 80 scfm Note: denotes user input value FLOW (gpd) Attachment 2 Page 1 of 1 LFG Condensate Estimate 80 scfm Attachment F

34 Project Name: FORT ORD LANDFILL - OU2 AREA F Date: 2/10/2003 Project No.: By: SN LFG CONDENSATE ESTIMATE LFG CONTROL SYSTEM DAILY GENERATION - SUMMARY TABLE PERIOD: WINTER SPRING SUMMER FALL TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) TEMP (F) AVG. HIGH AVG. LOW DAILY TOTAL PERIOD: 3 DAY WORST CASE 3 DAY BEST CASE LFG FLOW DATA TEMP (F) FLOW (gpd) TEMP (F) FLOW (gpd) AVG. HIGH MAX. SYSTEM VACUUM -70 in. w.c. AVG. LOW MAX. SYSTEM PRESSURE 15 in. w.c. DAILY TOTAL AVG. LFG WELL TEMP. 95 F MAX. LFG FLOW 94 scfm Note: denotes user input value FLOW (gpd) Attachment 2 Page 1 of 1 LFG Condensate Estimate 94 scfm Attachment F

35

36 Attachment 3 Pipe Size Calculations

37 Attachment 3 List Pressure Drop Chart for LFG Flow through Lateral Pressure Drop Chart for LFG Flow through Piping - Leg B (4 to 6 inch header) Pressure Drop Chart for LFG Flow through Piping - Leg B (6 inch header) Pressure Drop Chart for LFG Flow through Piping - Leg C (4 to 6 inch header) 1 Page 1 of 1 Attachment 3

38 PRESSURE DROP CHART FOR LFG FLOW THROUGH LATERAL Fort Ord - Area F Head loss calculation estimate for 350 ft 3" HDPE SDR-17 lateral 2/5/2003 H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Project: Flow at or IPS d L qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. EW Header EW Header EW Header Attachment 3 Page 1 of 1

39 PRESSURE DROP CHART FOR LFG FLOW THROUGH PIPING - LEG B (4 TO 6 INCH HEADER) Project: Fort Ord - Area F Head loss calculation estimate for current treatment equipment location, 700 ft. away from Leg B - Current flowrate operation, w/4 VS GACs, 5 VS ZK6; 4-inch hose between treatment vessels; Head losses based on maximum pressure drops provided by site for October 1, /5/2003 Blower at exhaust end of process. H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Flow at or IPS d L qt qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. flow velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow rate in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm acfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. EW EW EW EW EW EW EW EW EW EW EW kop in GAC 1/ GAC 2/ KMnO KMnO Attachment 3 Page 1 of 2

40 PRESSURE DROP CHART FOR LFG FLOW THROUGH PIPING - LEG B (4 TO 6 INCH HEADER) Project: Fort Ord - Area F Head loss calculation estimate for current treatment equipment location, 700 ft. away from Leg B - Current flowrate operation, w/4 VS GACs, 5 VS ZK6; 4-inch hose between treatment vessels; Head losses based on maximum pressure drops provided by site for October 1, /5/2003 Blower at exhaust end of process. H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Flow at or IPS d L qt qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. flow velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow rate in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm acfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. KMnO KMnO KMnO blower 1 in Accuflo exhaust TOTALS Attachment 3 Page 2 of 2

41 PRESSURE DROP CHART FOR LFG FLOW THROUGH PIPING - LEG B (6-INCH HEADER) PROJECT: Fort Ord - Area F Head loss calculation estimate for current treatment equipment location, 700 ft. away from Leg B - Current flowrate operation, w/4 VS GACs, 5 VS ZK6; 6-inch header; 4-inch hose between treatment vessels; Head losses based on maximum pressure drops provided by site for October 1, /5/2003 Blower at exhaust end of process. H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Flow at or IPS d L qt qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. flow velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow rate in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm acfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. EW EW EW EW EW EW EW EW EW EW EW kop in GAC 1/ Attachment C Page 1 of 2

42 PRESSURE DROP CHART FOR LFG FLOW THROUGH PIPING - LEG B (6-INCH HEADER) PROJECT: Fort Ord - Area F Head loss calculation estimate for current treatment equipment location, 700 ft. away from Leg B - Current flowrate operation, w/4 VS GACs, 5 VS ZK6; 6-inch header; 4-inch hose between treatment vessels; Head losses based on maximum pressure drops provided by site for October 1, /5/2003 Blower at exhaust end of process. H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Flow at or IPS d L qt qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. flow velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow rate in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm acfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. GAC 2/ KMnO KMnO KMnO KMnO KMnO blower 1 in Accuflo exhaust 1.38 TOTALS Attachment C Page 2 of 2

43 PRESSURE DROP CHART FOR LFG FLOW THROUGH PIPING - LEG C (4 TO 6 INCH HEADER) Project: Fort Ord - Area F Head loss calculation estimate for current treatment equipment location, 700 ft. away from Leg C - Current flowrate operation, w/4 VS GACs, 5 VS ZK6; 4-inch hose between treatment vessels; Head losses based on maximum pressure drops provided by site for October 1, /5/2003 Blower at exhaust end of process. H100=2.74*(q/((d*12)^2*3.14/4))^1.9/d^1.22 (equation used to develop the Crane friction loss chart) where: H100=friction pressure drop in 100 ft of pipe, inch W.C. q=gas flowrate,cu ft/min d=internal diameter of pipe, inches Flow at or IPS d L qt qt v H100 HL HL HL Pv NUMBER OF between pipe pipe pipe minor total trib. flow velocity headloss headloss process total suction MINOR LOSSES point or size size length losses equiv. flow rate in 100 ft in "L" ft units max. hard soft open node inch inch feet feet length scfm acfm f/s inch W.C. inch W.C. inch W.C. inch W.C. inch W.C. tees tees elbows valves red./exp. EW EW EW EW EW EW EW Tee kop in GAC 1/ GAC 2/ KMnO KMnO KMnO KMnO Attachment 3 Page 1 of 2